1. Field of the Invention
The present invention relates to a rotary powder compression molding machine for manufacturing a tablet and a food product, and further an electronic part and the like.
2. Description of the Related Art
Conventionally, for example, a medical tablet is manufactured by compressing a powder corresponding to a raw material of the medical tablet. A rotary powder compression molding machine for manufacturing such a tablet mentioned above is provided with a rotary turret, a plurality of dies arranged at a predetermined interval in a circumferential direction of the rotary turret, upper and lower punches arranged per the dies in such a manner that a leading end can be inserted into the dies, upper and lower rolls for generating a compression force in the punches, and a vertical shaft rotating the rotary turret. Further, in the case that the upper and lower punches pass through a portion between the upper and lower rolls, a powder filled within the die is compressed by the upper and lower punches, thereby forming a tablet.
In the rotary powder compression molding machine mentioned above, there has been known a machine structured such that the rotary turret can be detached from the vertical shaft, for manufacturing plural kinds of tablets by one machine, or for facilitating a cleaning within the machine. For example, in Japanese Unexamined Patent Publication No. H11-19799, there is described a gear coupling constituted by a pair of gears and provided annularly with a plurality of teeth each having a trapezoidal cross sectional shape, as a joint mechanism. The gear coupling is structured such that one of a pair of gears is attached to the vertical shaft, the other gear is attached to the rotary turret, and the respective teeth are engaged with each other so as to couple the rotary turret to the vertical shaft.
In accordance with the structure mentioned above, since the rotary turret and the vertical shaft are engaged with each other in the teeth of the respective gears, that is, a pair of gears are coupled in a state in which a pair of gears are not constrained in an axial direction of the vertical shaft, it is possible to easily cancel the engagement by pulling up the rotary turret so as to separate the rotary turret from the vertical shaft. As a result, it is possible to bring the rotary turret out of the machine, and it is possible to clean up and/or exchange the rotary turret.
However, as mentioned above, since the gear coupling is not in a state of being constrained in the direction of the axial core of the vertical shaft in such a manner that the respective gears are not separated from each other, a great force is applied to the respective teeth if the vertical shaft rotates and is going to rotate the rotary turret, and a force pushing up the rotary turret on the basis of the force is applied to the rotary turret. In order to prevent the rotary turret from floating up, in the Japanese Unexamined Patent Publication No. H11-19799 mentioned above, a sufficient force to cancel the upward force is applied to the rotary turret during a time when the rotary turret is coupled to the vertical shaft.
Accordingly, in comparison with the structure which is not provided with the joint mechanism mentioned above, a great force (load) is applied to a bearing supporting the vertical shaft, a useful life of the bearing is shortened. Further, since a mechanism for pressing the rotary turret is installed above the rotary turret, the mechanism takes much possession of a space within the machine, thereby enlarging a size of the machine.
Further, since the mechanism for pressing the rotary turret is necessary, there is generated a necessity of changing a layout of piping and wiring within a frame, and a layout of a mechanism for supplying the powder and the like with respect to a layout of a standard molding machine. Accordingly, an increase of a man-hour is caused in the manufacturing in addition to a designing, and a manufacturing cost is increased as a whole.
Further, since the joint mechanism is positioned between the rotary turret and the vertical shaft, it is impossible to visually observe the coupling state. Accordingly, even if the coupling is executed in a state in which a foreign matter is intervened between the teeth of the gear coupling, it is impossible to check the state.
Further, since various constituting parts structuring the mechanism mentioned above come close to a so-called tablet making area in which the upper punch above the rotary turret, a guide rail and the like are arranged, an efficiency of the cleaning work for the tablet making area and the mechanism is lowered.